Tissues, Glands, and Membranes Flashcards
What is the study of tissues called?
histology
What are tissues?
groups of cells arranged in a characteristic pattern that carry out a specific function
What are stem cells?
- immature undifferentiated cells with the potential to become different types of tissues (stem cells in red bone marrow can become many types of blood cells)
- embryonic stem cells can differentiate into every kind of tissue
What are the four main groups of tissues?
- epithelial
- connective
- muscle
- nervous
What does epithelial tissue do?
- covers surfaces
- lines cavities
- forms all glands
What does connective tissue do?
supports and forms framework for the body
What does muscle tissue do?
- contracts and produces movement - electrically excitable
What does nervous tissue do?
- communicates through nerve impulses - electrically excitable
What is epithelial tissue composed of?
tightly joined cells found in sheets or layers
What type of tissue is the protective covering for the body?
- epithelial tissue
- main tissue of outer layer of skin called epidermis
What tissue type lines glands and associated ducts, body cavities and hollow organs (lungs, stomach, bladder) and covers organs in body cavities?
epithelial
What tissue forms part of membranes?
epithelial
What are the classifications of epithelial cells by shape?
- squamous - flat
- cuboidal - square
- columnar - tall and narrow
What are the classifications of epithelial cells by arrangement?
- simple - single layer of cell
- stratified - 2 or more layers of cells
- pseudostratified - falsely appearing layered when not
What are four special features of epithelial tissue structure?
- cilia (sweep mucous-trapped particles, create current)
- microvilli (increase surface area of cell for absorption)
- goblet cells (produce mucous)
- keratin (tough protein)
What is simple squamous epithelium and where is it located?
- single layer of flat cells, thin and thus speeds up rate of diffusion
- lining alveoli of lungs (gas exchange)
- wall of capillaries (gas, nutrient, waste exchange with tissues)
- covering organs and lining organ cavities (mesothelium) (epithelium of serous membranes)
What is simple cuboidal epithelium and where is it found?
- single layer of square-shaped cells adapted for secretion and absorption
- lining kidney tubules and ducts of many glands (glands made of cuboidal epithelial cells)
What type of cells are glands made of?
cuboidal epithelial cells
What is simple columnar epithelium? What are the two types (purposes and location)?
- one layer of tall cells, tougher and more resilient than squamous or cuboidal cells
- ciliated simple columnar epithelia with goblet cells (lines respiratory tract eg nose and bronchi, traps airborne particles and sweeps them out)
- simple columnar epithelia with microvilli and goblet cells (lines small intestine, secretes mucous) (microvilli increase surface area for absorption)
What is structure and appearance of transitional epithelium?
- many layers of cells
- appearance ranging from stratified squamous to stratified cuboidal
What type of tissue lines urinary bladder and parts of ureter and urethra? What does it do in the bladder?
- transitional epithelium
- allows expansion of epithelial lining (appears squamous) but returns to original shape (cuboidal) when bladder emptied
What is stratified squamous epithelium and where is it found?
- many layers of flat cells that provide a barrier and resist friction
- found lining the mouth, vagina and anus
What do glands do?
- specialized to produce a substance sent out to other parts of the body
What are the two major types of glands?
- exocrine
- endocrine
What type of gland secretes substances into ducts that open onto a surface or into a lumen? What are some examples?
- exocrine glands
- sweat glands (open on to skin for cooling)
- salivary glands (open into mouth releasing saliva containing enzymes)
- goblet cells secrete mucous directly onto surface of mucous membranes
What type of gland secretes hormones into the blood (no ducts)? What are some examples?
- endocrine glands
- pituitary gland (human growth hormone)
- testes (testosterone)
What is connective tissue?
- widely scattered cells found in a non-living matrix
- supportive tissue with wide variety of functions
What does the matrix connective tissue is found in consist of?
- fibres (collagen - tough, elastic - stretchy)
- water
- minerals and other molecules affecting the consistency of the connective tissue (varying amounts)
How is connective tissue categorized?
by physical properties
What are fibroblasts?
cells of connective tissue that produce the matrix
What are the four types of connective tissue and their properties?
- circulating (blood and lymph)
- loose (jelly-like soft consistency)
- dense (contains many fibres)
- structural (bone, cartilage)
What are the types of loose and dense connective tissue?
- loose (areolar, adipose aka fat)
- dense (dense regular, dense irregular, elastic)
What type of tissue is areolar tissue and what are the properties? Where is it found?
- loose connective tissue
- binding and filler tissue; glues epithelia to next layer
- cells and variety of fibres in loose jelly-like matrix
- dermis of skin, wall of blood vessels and organs (does not line organs)
What type of tissue is adipose tissue and what are its properties? Where is it found?
- loose connective
- similar to areolar (binding, filler, cells & fibres in loose jelly matrix) but with adipocytes (cells that store fat)
- energy storage tissue
- acts as heat insulation layer
- protective padding around organs (kidney) and under the dermis (fat)
What is the difference between dense irregular and dense regular connective tissue? What are examples?
- both composed mostly of collage fibers but irregular in random arrangement providing strength in all directions and regular in parallel arrangement providing strength in one direction
- irregular (dermis of skin, fascia covering muscles, joint capsules)
- regular (tendons, ligaments)
What is elastic connective tissue composed of and where is it found?
- mostly of elastic fibers that return to resting length after stretched
- vocal cords, large artery walls
What are the types of structural connective tissue?
- dense irregular
- dense regular
- cartilage
- bone
What are the three types of cartilage?
- hyaline
- fibro
- elastic
Does cartilage contain blood vessels and regenerate? Does bone?
- cartilage no
- bone yes
What produces rubbery matrix of cartilage?
- chandrocytes with collagen
What are some properties of hyaline cartilage and where is it found?
- functions in shock absorption
- covers ends of long bones and reduces friction
- nose, voice box, windpipe
What are some properties of fibrocartilage and where is it found?
- stronger and rigid
- between vertebrae in spine and between pubic bones
- functions as cushion for areas of compression
What are some properties of elastic cartilage and where is it found?
- stretchy but returns to size; flexible
- allows for movement
- found in outer portion of ear, epiglottis
What type of tissue is bone made up of?
- osseous tissue
What two types of cells produce osseous tissue?
- osteoblasts (lay down matrix)
- osteocytes (mature cells that maintain living bone & lay down minerals to make it hard)
What are the type types of bone?
- compact bone (mineral storage, protection, framework)
- spongy bone (framework w/ large paces where red bone marrow is located and produces blood cells)
What tissue is electrically excitable and able to contract?
muscle tissue
What are the three main types of muscle tissue? Are they voluntary or involuntary?
- skeletal (voluntary)
- cardiac (involuntary)
- smooth (involuntary)
What does skeletal muscle do?
- works with tendons and bones to produce movement
- generates heat to maintain body temp
What type of muscle is striated and what does that mean?
- skeletal and cardiac
- organized muscle proteins produce visible bands
Where is cardiac muscle found and what is its properties?
- myocardium of heart
- involuntary, striated, branched
What are intercalcated discs?
- tough junctions to connect cell to cell
- a property of cardiac muscle that permits electrical current from pacemaker of heart to spread causing contraction
What are the properties, location, and function of smooth muscle?
(visceral muscle)
- involuntary, not striated, tapered at each end
- located in walls of hollow organs and blood vessels (beneath epithelia and areolar connective tissue)
- regulates volume, propels substances (peristalsis)
What tissue is electrically excitable and involved in communication using electrical signals?
nervous tissue
What is nervous tissue composed of?
- neurons (the functional cell)
- neuroglia (supportive)
Where is nervous tissue found?
- brain (central control region)
- spinal cord (site of reflexes and conducts signals to and from brain)
- nerves (fibers that conduct the electrical signals or nerve impulses (action potentials) to and from the brain and/or spinal cord
What is the neuron (in regard to nervous tissue)?
- functional unit of nervous tissue
- generates electrical signals for communication
What is the neuron composed of?
- cell body (most organelles located here)
- fibers projecting from cell body (dendrites conduct impulses toward cell body; one axon per cell conducts impulses away from the cell body)
What are nerves composed of and what do they do?
- bundles of axons and dendrites
- conduct impulses back and forth between brain/spinal cord and body
What are neuroglia (nervous tissue)?
- glial cells
- support cells of the nervous system
What do neuroglia do? What do they not do?
- protect brain, spinal cord, axons
- some produce myelin found around axons (myelin fatty insulation that speeds of conduction of electrical signals acting like electrical tape around wires)
- clean up debris and fight infection
- do not generate electrical impulses
What are membranes? What are they composed of?
- thin sheets of tissue
- epithelia on the free surface and areolar connective tissue beneath
What do membranes do? What do they secrete?
- line hollow organ or body cavity
- cover a surface
- anchor organs in abdominal cavity (mesentery)
- secrete watery substances (mucous, serous fluid, synovial fluid)
What are the two types of membranes?
- epithelial membranes
- synovial membranes
What are the subcategories of epithelial membranes?
- serous
- mucous
- cutaneous (skin)
Where are synovial membranes found and what do they do?
- line joint cavities
- no epithelial layer
- secrete synovial fluid that lubricates joints
What type of membranes line cavities that do not open to the outside (thoracic, pericardial, abdominal etc)?
serous membranes
What is the mesothelium and what does it do?
- epithelial surface of serous membranes
- produces thin layer of serous fluid that allows structures to slide past each other, prevents adhesions between organs, and acts as a barrier to prevent bacterial invasion)
What are the layers of the serous membrane and what do they do?
- parietal layer (lines body cavity)
- visceral layer (covers organ)
What are the three types of serous membranes and where are they found?
- pleura (lungs)
- pericardium (heart) (additional fibrous pericardium surrounds it)
- peritoneum (abdominal cavity)
What is the serous membrane of the lungs called?
pleura
What is the serous membrane of the heart called?
pericardium
What is the serous membrane of the abdominal cavity called?
periotneum
What type of membrane lines cavities that open to the outside? What are some examples of these cavities?
- mucous membranes
- urinary, reproductive, digestive, and respiratory tract linings
What are the types of epithelial layer structures of the mucous membranes and their functions?
- mucous and cilia trap and remove foreign particles (airways)
- stratified epithelium protects deeper tissue (mouth, respiratory/digestive)
- epithelia with microvilli absorbs food materials (small intestine)
What happens to tissues as they age?
- lose elasticity and become less flexible
- sagging, wrinkles
- repair less easily
What happens to blood vessels as we age?
blood vessels lose ability to expand with bursts from heart leading to high blood pressure
What happens to tendons and ligaments as tissues age?
stretch leading to poor posture and joint instability
What happens to bones as tissues age?
become brittle leading to fractures
What happens to muscles as tissues age?
atrophy or lose muscle cells and are replaced with connective tissue
What is the superficial layer of epithelial membranes made of? The deep layer?
- epithelium
- connective tissue
What are the three types of epithelial membranes and where are they found?
- serous (line body cavities & cover internal organs)
- mucous (line tubes and ducts that open to outside of body)
- cutaneous (skin)
What are serous membranes?
epithelial membranes that line body cavities and cover internal organs
What are mucous membranes?
epithelial membranes that line tubes and ducts that open to outside of the body
What are cutaneous membranes?
epithelial membrane commonly known as skin
What are connective tissue membranes composed of?
connected tissue with no epithelium
What are the four types of connective tissue membranes?
- synovial membranes
- meninges
- fascia
- membranes that surround organs
What are synovial membranes? Where are they found?
- connective tissue membranes
- line joint cavities and secrete synovial fluid which lubricates joints
- line small cushioning sacs near joints (bursae)
What type of membrane is meninges? Where found?
- connective tissue membrane
- covering brain and spinal cord
What are the two types of fasica?
- superficial (underneath skin, insulates body)
- deep (covers, separates, protects skeletal muscles)
What type of membrane is the fascia?
connective tissue membrane
What type of fascia is underneath the skin, insulating the body?
superficial fascia
What type of fascia covers, separates, and protects skeletal muscles?
deep fascia
What are some membranes that surround organs?
- fibrous pericardium surrounds heart
- periosteum surrounds bone
- perichondrium surrounds cartilage
What type of membranes are those that surround organs?
connective tissue membranes
